#include <list>
#include <memory>
#include <iostream>
using namespace std;
 
struct mybase{
    virtual void proc(){
        cout << "I'm mybase" << endl;
    }
    virtual ~mybase() {} // don't forget this!
};
 
struct myderiv: public mybase{
    void proc(){
        cout << "I'm myderiv" << endl;
    }
};
 
int main(){
    myderiv a;
    a.proc();
 
    mybase *b = &a;
    b->proc();
 
    list<unique_ptr<mybase>> c;
    c.push_back(unique_ptr<mybase>(new myderiv(a)));
    list<unique_ptr<mybase>>::iterator it = c.begin();
    (*it)->proc();
 
    return 0;
}
 

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